peakdetect.py

import math
import struct
import wave
import sys

w = wave.open(sys.argv[1], 'rb')
sum = 0
value = 0;
delta = 0;
amps = []

for i in range(0, w.getnframes()):
    # Assume stereo, mix the channels.
    data = struct.unpack('<hh', w.readframes(1))
    sum += (data[0] * data[0] + data[1] * data[1]) / 2
    # 44100 / 30 = 1470
    if (i != 0 and (i % 1470) == 0):
        value = int(math.sqrt(sum / 1470.0) / 10)
        amps.append(value - delta)
        delta = value
        sum = 0

print(amps)